Are you a homeowner in Florida? Do you have citrus on your property? Consider helping the University of Florida/IFAS Extension by taking a survey!
This survey is part of a research project carried out by the UF/IFAS to gather information on citrus pests in residential settings in Florida. This survey is designated for Florida residentswho have citrus on their property that are not intended for commercial use. The outcomes of this survey will serve to develop appropriate control methods against critical citrus pests for dooryard citrus. We kindly ask that you complete all questions on this survey which will take approximately 20 minutes.
The University of Florida is conducting a survey among Florida homeowners that have citrus on their property. This survey is supported by USDA-NIFA and is about pests that might be found on citrus and how to manage them. The survey should take only 10 min and will help the University of Florida to develop an Extension program adapted to residential areas.
Thank you for your help!
Citrus: Bearing Branches. Image Credit Matthew Orwat, UF/IFAS
We often think of plant pests to be only insects. However, plant pests can also be fungal and bacterial diseases, weeds, and even rodents. That’s right, rodents, like squirrels, mice, and rats! One particularly annoying rodent pest of the garden is the roof rat (Rattus rattus, a.k.a. citrus rat, fruit rat, black rat, or gray rat). Roof rats are native to southern Asia. This is the same species that was responsible for carrying the bubonic plague around the world. Roof rats are the most detrimental rodent pest to fruit crops in the state of Florida. In addition to fruit crops, they feed on stored animal and human food. Roof rats live in attics, soffits, walls, and outbuildings. They also chew through wires, pipes, and walls. Roof rats damage some fruit crops (like citrus and melons) by first creating a half dollar sized hole, then they hollow out the fruit. In crops without a rind or peel, like peaches and tomatoes, they just eat large chunks.
Roof rat damage to tangerines. Photo Credit: Matt Lollar, University of Florida/IFAS Extension – Santa Rosa County
Adult roof rats are 12-14 inches long with tails longer than their body length. In Florida they have been identified in three color phases: black back with gray belly; gray back with light gray belly; and brownish gray back with a white or cream colored belly. Other than fruit damage, evidence of infestation includes 1/4-1/2 inch long droppings and rub marks left along travel trails. Roof rats will travel up to 150 yards from their den for food and water. They breed year-round and have litters of 5-8 pups with a gestation period of only 21 to 23 days.
An adult roof rat. Photo Credit: Alabama Cooperative Extension System
A well-thought-out integrated pest management strategy is needed to control and potentially prevent roof rats on your property. Integrated pest management is a strategy consisting of multiple tactics to control a pest. These tactics include scouting (looking for evidence of the pest population); prevention; trapping and exclusion; biological control such as predators; and rodenticides and repellants.
Prevention – Roof rats are good climbers and swimmers. It is important that fruit trees are planted away from the house, fences, and outbuildings. Make sure to prune fruit trees away from these structures if they can’t be removed or transplanted to another location. Also prune branches from touching the ground to help prevent rats from using trees for cover. Sheet metal (18-24 inches wide) can be loosely wrapped around the tree trunk to keep rats out of the tree.
Trapping – Rat traps can be placed in several strategic locations. Traps (triggers facing down) can be attached to the trunks of trees. Traps can also be attached to the stringer boards on a fence. Make sure that traps are only set from dusk to dawn to avoid killing non-target species like birds and squirrels. Leave traps in place for at least a week before moving them because roof rats are cautious of new objects.
Rodenticides & Repellants – Poisons should only be used after all other control methods are exhausted. Most products are very toxic to humans, pets, and wildlife. If used outdoors, poison baits must be placed in tamper-resistant bait stations.
Biological Control – Rat snakes and king snakes are good natural predators for roof rats. If you have more open spaces you may consider building a barn owl house. Barn owls and hawks are also natural predators. You may also consider getting a farm cat to help control the population. Cats will kill juvenile rats, but have trouble catching adult rats.
Hopefully you will never have to encounter roof rats or other rodents invading your yard and house. However, if they do come around more information is available in the publication “Pests in and Around the Southern Home“.
Violas. Photo Credit: University of Florida/IFAS Extension
It is freezing cold this week and hard to believe that we are already talking about “What to Plant” and “What to Do” to get started early. In North Florida there are cool-season annuals that can be planted now. The list includes pansies, violas, petunias, and snapdragons. As we are coming to the end of January it is time to plant crinum, agapanthus and gloriosa lily bulbs. Make sure to mulch these areas after planting to protect them from the cold temperatures. This is also the month to plant camellias, which these come in many colors and forms that your local nurseries will carry this time of year. If you haven’t planted all your cool season crops there is still time to do that now such as broccoli, kale, carrots, and lettuce. Irish potatoes can be planted now as well.
Now you might be asking “What can I do?”. January is a great time to prune non-spring flowering shrubs and trees to improve their form. This is a good time to plant deciduous fruit trees, this will give their roots time to develop before the warmer spring temperatures. Since existing trees are dormant, it is a good time to prune and fertilize them. When the temperatures are near freezing many of the tender plants will need to be covered to minimize damage. It’s a good time to plant a tree. Hurricane-resistant trees include live oaks, bald cypress, cabbage palms, and southern magnolias. It’s time to remove those dead spent seed pods on your crape myrtles and removing any crossing branches and twiggy growth will improve the appearance and the form of the plant.
Potatoes planted in mid-February were ready to harvest in mid-May in Bay County. Photo: Vicki Evans, UF/IFAS Master Gardener of the plant.
As we go into February it will soon be time to apply a preemergence weed killer to your lawns to prevent warm-season weeds. Temperatures must rise to 65°F for 4 to 5 consecutive days before you do a preemergence application and make sure you are not using a weed and feed fertilizer. Citrus and other fruit trees can be fertilized at this time. The amount and frequency will depend on the age and type of fruit tree you are growing. Avoid pruning Citrus until spring to avoid any injury since cold temperatures are still possible. It is time to prune those roses this month to remove damaged canes and improve the overall form. After the pruning is complete you can fertilize and apply a fresh layer of mulch. They should begin blooming within 8 to 9 weeks after being pruned.
Dianthus, pansies, violas, and dusty millers are annuals that can take a chill and should be planted in February. You can continue to plant crinum and agapanthus this month and add on amaryllis and rain lily bulbs as well. If it has been dry make sure to provide plenty of water for the bulbs to establish and continue to protect them from the cold by adding mulch. Trees and shrubs will begin to bloom this month including red maples and star magnolias. Continue planting potatoes throughout the month and towards the end of February warm-season crops like tomatoes and pepper can be planted but be prepared to protect them from any late frosts.
Asian citrus psyllid, Diaphorina citri. UF/IFAS/Entomology Photo: Michael Rogers.
In late 2016, as many of us were enjoying the harvests from our backyard citrus, a bacterial plant disease that can affect all citrus, citrus greening, was widespread in central and south Florida but had not made it this far north. That year, the vector, the insect that spreads the disease from tree to tree, had been found in Leon County and a few other surrounding Panhandle counties, but the disease had not. By mid-2017, the disease had been confirmed in Franklin County and we hoped that our cooler temperatures could keep the insect and disease at bay. Well, I regret to inform you that the disease has also now been confirmed in Leon County, growing in a residential yard in Tallahassee. Now that it is confirmed in non-coastal (and cooler) north Florida locations, I thought a review of the signs and symptoms – as well as what to do with your tree if you suspect or confirm greening – would be helpful.
The tricky part about diagnosing citrus greening is that it has symptoms that look very similar to soil nutrient deficiency symptoms, especially when first infected. This is a good time to mention that citrus require certain micro-nutrients for optimal growth and a citrus-specific fertilizer product should be used when applying fertilizer. Both the disease and certain nutrient deficiencies cause yellowing of the leaves. With greening, the yellowing is typically blotchy and/or not in any particular pattern. Nutrient deficiencies typically cause unique patterns of yellowing, such as a V-shape or artistic-like symmetrical patterns on each side of the leaf’s midvein. The soil’s acidity, or pH, can also cause some nutrients to not be taken up by the plant even if they are present. Soil testing, available from your local UF/IFAS Extension office, and scheduled fertilizations with a citrus-specific fertilizer can ensure that nutrients are not to blame for the discoloring of leaves. More advanced stages of the disease cause such symptoms as leaf drop, fruit drop, lop-sided fruit, uneven inner fruit cores, and reduced fruit quality.
Citrus greening symptoms of the fruit. Photo by Brooke Moffis.
A more obvious sign of potential problems for your citrus are the presence of the insect vector, the Asian citrus psyllid. This is a tiny little insect that goes from one leaf to the other sucking up plant saps for food and unknowingly spreading the bacterium responsible for citrus greening. You can monitor for them by looking closely at the new flushes of growth. If the psyllids are present, you will likely notice most their small, peach-colored eggs and/or white, waxy secretions. If found, it doesn’t necessarily mean that your tree has greening, but you will want to minimize the chance that they could carry it to your tree. The psyllids can be treated with pesticides, ranging from the less harsh options (horticulture oils, neem oil, kaolin clay) to the more hardcore stuff (malathion, carbaryl, imidacloprid). Of course, always read the label of any pesticide before use and/or consult a qualified landscape professional for assistance.
Blotchy leaf symptom of citrus greening. Photo by Jamie D. Burrow.
If you suspect your tree is infected, a diagnostic test can be performed by UF/IFAS plant pathologists at the North Florida Research and Education Center (NFREC) in Quincy to confirm. The test does cost $50, which may seem a little steep, but it’s an expensive lab analysis to run and may be worth piece of mind.
If citrus greening is confirmed in your tree, the right thing to do, unfortunately, is to remove and burn the plant material as there is no known cure. While the Florida Department of Agriculture and Consumer Services (FDACS) doesn’t have any removal requirements for infected dooryard citrus, tree removal is best to prevent additional spread of the disease to other trees, especially those grown by commercial producers in our area. This may seem drastic but eventually the health of the tree and quality of the fruit will decline to a point where you will want to remove it anyway. Don’t forget that movement of any citrus plant outside of the state is prohibited for the very reason of preventing spread of citrus diseases.
You may be asking, “Is it okay to replace it with another citrus tree?” The answer is yes you can, but you do risk re-infection and will want to be monitoring the new planting.
You may also be thinking, “What is going to happen to Florida citrus?” That’s a question that many researchers at UF/IFAS are trying to answer. There is some hope that intense irrigation and nutrient management, as well as specific pruning practices, can help infected trees continue to be profitable for commercial growers. Recently, UF/IFAS researchers were awarded several grants to try and figure a way out of this problem. Some of the lines of research focus on exploring the resistance found in different citrus varieties, including an Australian lime that appears to be greening resistant. This could potentially be used as a future rootstock. Another approach is to try and treat the plants with a particular peptide that would prevent the disease from binding in the insect’s gut. Isn’t that amazing?
Until a fix is found, we should be monitoring for this disease in our area and taking steps to reduce its presence through controlling the psyllids and removing infected trees. If you suspect a tree has greening, please contact your local county Extension office to review the symptoms and discuss your options.
